Engineers achieve pure titanium powder, offering the marketplace a new option

April 2015 - Technology continues to evolve, driving industry demands for purer materials that are potent enough to handle/tackle increasingly challenging end uses. To innovate, it’s sometimes necessary to take a step back and approach an old process with a fresh perspective. The unavailability of contaminant-free titanium powder coupled with the higher cost associated with titanium meant that manufacturers simply opted for lower-cost, and lower performance materials for most applications.

Achieving zero contamination when processing titanium is essential. By ensuring the powder is exposed to nothing other than titanium throughout the entire production process, Puris LLC has devised a method to keep the powder pure. During traditional gas atomization processes, powder is processed through a ceramic nozzle; small particles of that refractory can enter the powder and be detrimental to the end part’s performance. Puris alleviated that risk with a refractory-free process.

“If a part is going to fail it will fail at its weakest spot. This spot will always be where there is any level of contamination,” explains Craig Kirsch, CEO at Puris, Bruceton Mills, West Virginia. “Design engineers are well aware of these risks and well aware that contamination is a fairly widespread concern.” 

Another common source of contamination occurs in components of the gas atomizer that are typically made of stainless steel. “The very nature of making titanium powder is a violent process,” Kirsch says. “Hot powder is flying around hitting the sides of the atomizer. As the powder hits the sides of a stainless steel system, inevitably some of the stainless steel is stripped off during the process. 

“Our engineers designed a patent pending, all-titanium system that ensures the only material the hot titanium touches throughout the process is titanium,” he continues. “There is no refractory anywhere in our system and there is no stainless steel. Our powder doesn’t even encounter outside air during processing, which is why the titanium powder we produce is the purest in the world. That’s the inspiration behind our name.”

Innovative minds rethink process

The timing behind this innovation is perfect because in the past, the industry didn’t need pure titanium for automotive parts and less demanding applications. “But in a turbine for a jet engine, purity is a big deal,” according to Kirsch.

The company’s know-how is spearheaded by Technical Fellow Fred Yolton—affectionately known as “the godfather” for his extensive expertise and achievements in the titanium powder-making process. Yolton was part of the team that invented bottom-pour gas atomization in the early 1980s, technology that resulted in the ability to commercialize the powdered form of titanium. “We brought him on board to guide our technical experts and our continuing R&D efforts,” says Eric Bono, vice president of engineering solutions. “He leads a team of engineers that focus on advancing the process of making and using titanium powders.”

Puris’ team of metallurgy experts are focused on accelerating headway in the area of process purity and solving technical challenges to take additive manufacturing with titanium powder from an innovation into mainstream manufacturing. With the right leadership at the helm, “we’re able to think long term and allow these minds to be creative,” Bono says.

Titanium is gaining traction as technology advances in large part due to the alloy’s compelling strength-to-weight ratio, which is the highest of any metal element. Even though the metal is the ninth-most abundant material in the earth, it’s very expensive to extract and process. “Until now there’s been limited market for titanium parts, except in segments like aerospace where its performance characteristics are imperative,” Bono says. 

But additive manufacturing and 3-D printing are changing the outlook for certain materials, making it more cost effective to print parts from titanium powder. “During the machining process, if you’re machining a forged disc into a part, you might waste 100 pounds in machining chips to get one pound of part,” explains Bono. “But now, that one pound of part can be made from just 1.25 pounds of powder or even less. As additive manufacturing is maturing demand is increasing, and that’s a game-changer for titanium powder.”

Instead of losing titanium during the manufacturing process—taking a block of titanium and shaving it away (hence the term subtractive manufacturing)—you consume just the material you need to create the part. “With additive manufacturing, you’re using powder and titanium for the part much more efficiently. It brings costs more in line,” Bono says. 

From prototype to production

When clients come to Puris, timing is usually an important consideration. For standard titanium alloys, “We can typically turn those orders around in a few weeks,” Kirsch says. “If someone wants a non-traditional alloy or custom alloy, it naturally can take longer, up to six to eight weeks. But these are far shorter turnaround times than the industry standard had been.”

Puris’ annual capacity is 300,000 pounds. “That’s quite a significant number,” Kirsch says. “The big players in the industry we’re working with don’t have to worry about piecing together suppliers because we can be a full-force production scale for titanium powder.”

Until now, additive manufacturing has been used primarily to replace existing part designs. “The next phase, where the real innovation is going to come, is where part A can be totally reconceived with only its function in mind, without having to consider manufacturability,” Bono says. “Engineers can design a part without worrying about how to manufacture it.” 

Aerospace manufacturers can now take into consideration using titanium in more applications because it can be designed and printed using additive manufacturing. 

The question of “How does she join or weld it?” is no longer an issue, says Bono. Before 3-D printing capabilities, a part would come in 20 separate pieces that would need to be bolted or riveted together to create the final part. “Instead, we now come up with one single component that is printed,” he says.

To further explain the potential and impact of the technology, timing also has been drastically affected by using additive manufacturing with titanium powder. “Titanium forgings for aerospace materials can require 24-month-long lead time,” Bono says. “So it took two years to get parts completed. Today you can design and print something out in a few weeks.”

How is that possible? Creating a blade for an aerospace application, for example, often requires that parts be forged. “You have to make very expensive tooling and dies and you have to test them,” Bono says. “It’s a very long process and if you make a mistake with the tooling and it’s too large, for example, you have to start over and go through it all again. If you print something wrong, you just reprint … The capability here is truly revolutionary.” MM